When you thrash someone, you beat them — literally, with your fists, or figuratively, by winning a game or competition.

You can describe your game plan for a chess match this way: “I plan to thrash that show-off in just ten moves.” You can also threaten to physically thrash someone, like a neighborhood bully who’s been known to thrash much smaller kids. Thrash was originally a sixteenth-century variation on the word thresh, which means to separate grain from wheat or another plant by beating it.